Find the area under the standard normal curve between z=0 and z=3.
The lengths of pregnancies of humans are normally distributed with a mean of 268 days and a standard deviation of 15 days. A baby is premature if it is born three weeks early. What percentage of babies are born prematurely?
The distribution of cholesterol levels in teenage boys is approximately normal with and (Source: U.S. National Center for Health Statistics). Levels above 200 warrant attention. Find the probability that a teenage boy has a cholesterol level greater than 225.
An airline knows from experience that the distribution of the number of suitcases that get lost each week on a certain route is approximately normal with ? = 15.5 and Ï? = 3.6. What is the probability that during a given week the airline will lose less than 20 suitcases?
Assume that blood pressure readings are normally distributed with and A blood pressure reading of 145 or more may require medical attention. What percentage of people have a blood pressure reading greater than 145?
Assume that the salaries of elementary school teachers in the United States are normally distributed with a mean of $32,000 and a standard deviation of $3000. If a teacher is selected at random, find the probability that he or she makes more than $36,000.
IQ test scores are normally distributed with a mean of 100 and a standard deviation of 15. Find the x-score that corresponds to a z-score of -1.645.
For the standard normal curve, find the z-score that corresponds to the 90th percentile.
Find the z-scores for which 90% of the distribution's area lies between -z and z.
The solution provides answers to multiple choice questions on normal probability. Relevant workings are also included.